IMMUNOLOGICAL RESPONSIVENESS AND TOLERANCE OF MARMOSET LYMPHOID TISSUE IN VITRO

SUMMARY Unidirectional mixed lymphocyte culture (MLC) reactions were investigated to determine the feasibility of assessing in vitro histocompatibility in two species of marmosets. When lymph node cells from white-lipped marmosets were mixed in allogeneic or xenogeneic MLCs, there was an enhanced incorporation of 14C-thymidine in comparison to autologous mixtures. Peak response was at 5 days. In contrast, cotton-top marmoset allogeneic mixtures showed weak responses with no enhanced label uptake when cultured for a period of 8 days. When blood lymphocytes were cultured in the same medium used to assay histocompatibility with lymph node cells, there was little difference between the values for MLCs and responding cells alone. This might be explained by the fact that marmoset blood is known to transform blastically and proliferate myeloid elements in vitro. Modification of the culture medium produced significant responses in xenogeneic MLCs with blood lymphocytes; however, allogeneic MLC values were not significantly different from tolerant cotwin MLC values. Lymph node MLC response with cells from a kidney graft recipient that died on day 302 postsurgery failed to show specific sensitization to donor cotwin antigens